Mining apparatus



Nov. 16, 1965 D. H. H. BOLTON ETAL MINING APPARATUS Filed April' 20, 1964 2 Sheets-$heet l EME B E ATTORNEY! 1965 D. H. H. BOLTON ETAL 3,217,605

MINING APPARATUS 2, Sheets-Sheet 2 Filed April 20, 1964 INN/E NTOR S A w 66 R SLN O r I T T o r A P/w n SC ma A84 03% (a? D Y B United States l atent C) l 3,217,605 MINING APPARATUS Douglas Herbert Hewlett Bolton, Winchcombe, Frank Pawling, Charlton Kings, @heltenham, and Michael Charles Potts, Prestbury, Cheltenham, England, assignors to Dowty Mining Equipment Limited, Gloucester, England, a British company Filed Apr. 20, 1964, Ser. No. 360,882 Claims priority, application Great Britain, Apr. 22, 1963, 15,826/63 7 Claims. (Cl. 91-170) This invention relates to mining apparatus.

The present invention provides mining apparatus including a series of advanceable roof supports, each roof support having at least one fluid-pressure-operated prop for setting the support against a mine roof, a fluid-pressureoperated jack operable to advance the support, and a valve assembly controlling the supply of fluid under pressure to the prop and to the jack, the valve assembly including a valve which is actuated by the completion of a pre-determined advance of the support, with the support released from the roof, to cause resetting of the support against the roof, and the apparatus also including additional means operable to actuate the valve assembly of each support to cause automatic resetting of the support against the roof in the event of failure of the support to advance the predetermined distance, or in the event its resetting does not occur within a given period following its advance.

Each roof support may be caused to undergo an ad vancing operation by the receipt of a signal indicating the satisfactory resetting, after advance, of the previous support in the series. Operation of the additional means may cause a resetting signal to be sent to all the roof supports in the series.

I The additional means, when operated, may supply an electrical signal, or may supply a fluid pressure signal, to the valve assembly of a roof support to cause resetting of the support.

The additional means, when operated, may actuate the same valve as, or a valve different from, the valve which is actuated by the completion of the predetermined advance of the support.

The additional means may be manually operable at a position remote from the supports or it may be arranged to operate automatically if a support has not reset within a predetermined time after its advance.

One embodiment of the present invention will now be described, by way of example, with reference to the accompanying drawings of which,

FIG. 1 is a diagrammatic view of mining apparatus with the hydraulic connections omitted,

FIG. 2 is a diagrammatic view of part of the mining apparatus showing the hydraulic connections between the power unit and the roof supports, and

FIG. 3 is a diagrammatic view of the hydraulic valve assembly of a roof support, such as incorporates the present invention.

With reference to the accompanying drawings, mining apparatus includes a conveyor 1 extending along the working face 2 of a coal mine and a cutting machine 3 which travels along the working face 2 and is situated between the working face 2 and the conveyor 1. The mining apparatus also includes an advanceable roof support assembly including a series of roof supports 4 located on the opposite side of the conveyor 1 to the working face 2 and cutting machine 3. Each roof support 4, in the form illustrated, includes a groundengaging sole beam 5 carrying three hydraulically-operable telescopic props 6, and the three props 6 carry a roof beam (not shown). Each roof support 4 is connected to the conveyor 1 by a hydraulically-operable single-acting jack 7 for advancing the roof support 4 towards the conveyor 1 and every fourth roof support 4 has a hydraulically-operable doubleacting jack 8 for advancing the conveyor 1 relative to the roof supports 4. The jack 8 is not connected to the conveyor 1 and engages the conveyor 1 only when applying an advancing force to it.

The advanceable hydraulic roof support assembly also includes a hydraulic power unit 9 which has a main pressure source 10 from which a line 11 supplying hydraulic fluid under pressure extends along the series of roof supports 4. Each roof support 4 has a valve assembly 12 connected to the supply line 11 by a branch supply line 13. A hydraulic fluid return line 14 also extends along the series of roof supports 4, and the valve assembly 12 of each roof support 4 is connected to the return line 14 by a branch return line '15. The power unit 9 also includes two secondary hydraulic pressure sources 16, 17. A pilot line '18 connected to the secondary pressure source 16 passes through the valve assembly 12 of each roof support 4 in turn. A control line 19 extends from the secondary pressure source 17 along the series of roof supports 4, and the valve assembly 12 of each roof support 4 is connected to the control line 19 by branch control lines 21, 22.

As shown in FIG. 3, the valve assembly 12 of each roof support 4 with a double-acting jack 8 includes six valve units A, B, C, D, E and F. Valve unit A controls the supply of hydraulic fluid to the jack 8 in a. jack-extending sense and is connected to the branch supply line 13 and to a line 23 leading to the jack 8. Valve unit B is connected to the line 23 and to the branch return line 15.

Valve unit D controls the supply of hydraulic fluid to the jack 7 and jack 8 in a jack-contracting sense and is connected to the branch supply line 13 and to a line 24 leading to the jacks '7 and 8. Valve unit C is connected to the line 24 and to the branch return line 15. Valve unit E controls the supply of hydraulic fluid to the props 6 and is connected to the branch supply line 13 and to the props 6 through a line 25 including a restrictor 26 and a nonreturn valve 27. Valve unit F controls the release of hydraulic fluid from the props 6 and is connected to a line 28 leading from the props 6 and to the branch return line 15. The line 28 includes a nonreturn valve 29, and a pressure relief valve 31 is connected in parallel with the valve unit F between the line 28 and the branch return line 15.

The valve units A and B are associated with a pivotallymounted lever 32 which is connected to a similar lever 33 associated with the valve units C and D. The levers 32 and 33 co-ordinate the action of valve units A, B, C and D. In those roof supports without a double-acting jack 8, valve units A and B and lever 32 are omitted. The action of valve units E and F are co-ordinated by a pivotallymounted lever 34. The levers 32, 33 are ganged to one another as shown by the connection 30. Levers 32, 33 and 34. enable the valve assembly 12 to be operated manually if desired.

The valve assembly of each roof support 4 includes a pilot valve 35 which, before an advance of the roof supports begins, closes the pilot line 18. The pilot valve 35 includes a piston 39 carrying a piston rod 41. The piston 39 can be moved against the force exerted by a spring 42 by a suflicient hydraulic pressure in a line 43 to cause the piston rod 41 to lift the valve member 36 off the valve seat 31. The line 43 includes a non-return valve 44 and is connected to the line 25. The piston rod 41 has a bore 45 which, when the piston rod 41 is not engaging the valve member 36, brings one side of the valve member 36 into communication with the branch return line 15. When piston rod 41 engages the valve member 36, the valve member 36 closes the bore 45.

A locking valve 46 is connected to the pilot valve 35 and to the branch control line 21 in such a manner that hydraulic fluid trapped between piston 39 and non-return valve 44 can be released to the branch return line through the locking valve 46 by pressurising control line 19 and the branch control line 21 to cause a piston 47 to move a piston rod 48 into engagement with a valve member 49 and lift it off its valve seat 51 against the force exerted by a spring 52.

A prop re-setting valve 53 is associated with the supportadvancing jack 7. The re-setting valve 53 includes a valve member 54 urged by a spring 55 onto a valve seat 56 to isolate the chamber 57 of the jack 7 from a line 58 connected to valve unit F and to line through a nonreturn valve 59. A piston rod 61 carrying a piston 62 can be moved to lift the valve member 54 ofi? its seat 56, as the jack 7 becomes fully contracted, by a trip 63 carried by the piston rod 64 of the jack 7. The branch control line 22 is connected to the re-setting valve 53 and, when the control line 19 and branch control line 22 have been pressurised to a predetermined value, lower than the pressure required to open locking valve 46, the hydraulic pressure acts on the piston 62 to move the piston 62 and piston rod 61 and cause the valve member 54 to be lifted off its seat 56 by the piston rod 61. The re-setting valve 53 may be self-latching by arranging that when the valve member 54- has been lifted off its seat 56, the hydraulic pressure in line 58 maintains the valve in that position.

FIG. 1 shows the cutting machine 3 travelling from left to right along the working face 2. After the cutting machine 3 has passed the first few roof supports 4 in the series, it is necessary to advance the conveyor 1 in front of these roof supports 4 and then to advance the roof supports 4. Each roof support 4 having a conveyor-advancing jack 8 is operated to cause the jack 8 to apply an advancing force to the conveyor 1, the roof support 4 being set against the roof and acting as an anchorage. This is achieved by pivoting lever 32 in an anti-clockwise direction to open valve unit A and thus pressurise the line 23 and the pushing side of jack 8. This movement of the lever 32 may be caused by manual operation of lever 32 or by pressurisation of a hydraulic line 65 connected to valve unit B. The line 65 may be connected through a manually or remotely controlled valve to the main supply line 11. After the lever 32 has been pivoted in the anti-clockwise direction to cause the jack 8 to be pressurised in the conveyor-advancing sense, a springoperated latch 66 holds the lever 32 in this position. The anti-clockwise movement of lever 32 causes a similar movement of lever 33, but such movement does not change the state of valve units C and D from that shown in FIG. 3. The latch 66 is connected to the pilot line 18 in such a manner that pressurisation of the pilot line 18 releases the latch 66 so that valve unit A closes and returns lever 32 and consequently lever 33 to the position in FIG. 3.

When the first portion of the conveyor 1 has been advanced, as shown in FIG. 1, the roof supports 4 can then be advanced. The pressure source 16 in the power unit 9 is operated to pressurise line 13 and hence a hydraulic pressure signal is sent along line 18 to the first roof support 4. Referring now to FIG. 3, the hydraulic pressure signal reaches the roof support through the portion of line 18 shown in the upper lefthand part of FIG. 3. The hydraulic pressure signal releases the latch 66 and operates on valve unit C to cause clockwise movement of levers 33 and 32. As a result, valve unit A closes, valve unit B opens, valve unit C closes and valve unit D opens. Thus the pushing or jack-extending side of jack 8 is connected to the branch return line 15, and the jackcontracting sides of the jacks 7 and 8 are connected through the line 24 with the branch supply line 13.

The conveyor-advancing jack 8 is not actually connected to the conveyor 1 but merely pushes against the 1 conveyor 1 when applying an advancing force to it. Therefore, at this stage, the jack 8 contracts and takes no part in advancing the support.

Line 24 is also connected by a line 69 to valve unit F, and the pressurisation of line 24 causes the valve unit F to be opened to bring the line 28 into communication with the branch return line 15, thus releasing the hydraulic pressure in the props 6 and so releasing the roof support 4 from the roof. The jack 7 then contracts and advances the roof support 4 towards the conveyor 1 with the conveyor 1 acting as an anchorage.

When the jack 7 is fully contracted, or in other words when the roof support is fully advanced up to the conveyor 1, the trip 63 on the piston rod 64- of the jack 7 engages the piston rod 61 and opens the re-setting valve 53. The line 58 is therefore brought into communication with the main supply line 11 through the branch supply line 13, valve unit D, line 24, jack 7 and re-setting valve 53. The pressure in line 58 acts upon valve unit F to close it and then passes through non-return valve 59, restrictor 26 and non-return valve 27 to extend the props 6 and so reset the roof support 4 against the roof.

The hydraulic pressure in line 58 is also present in line 43. When the props 6 have been extended to give a satisfactory roof-supporting force, as evidenced by a build-up of pressure in line 43 to a predetermined value, this value of pressure is arranged to operate on the piston 39 and open pilot valve 35. Thus the portion of the pilot line 18 between the power unit 9 and the first roof support 4 is brought into communication with the portion of the pilot line 18 between the first roof support and the second roof support (that is the portion of the pilot line 18 in the lower left portion of FIG. 3) with the result that the hydraulic pressure signal in the pilot line 18 reaches the second roof support in the series and causes it to undergo an advancing operation. In this way, each roof support in turn is advanced. The locking valve 46 and the non return valve 44 trap hydraulic fluid to lock the pilot valve 35 in the open position.

If any roof support 4 fails to advance the full amount, for example if there is an obstruction in its path, the jack 7 will not become fully contracted and the re-setting valve 53 will not be opened. Hence the props 6 will not automatically re-set the roof support against the roof and the pilot valve 35 will not be opened. Therefore, the hy draulic pressure signal will not be passed on along the pilot line 18 to the next roof-support, and the advancing operations of the roof supports will stop.

If this happens, the re-setting valve 53 can be opened by manually operating the power source 17 to pressurise the control line 19 and the branch control line 22 to such a predetermined value that the hydraulic pressure in branch control line 22 operates on piston 62 to open the valve 53. When the re-setting valve 53 is self-latching, pressure is required in the control line 19 and branch control line 22 for only a short period. Thus the props 6 are then extended to reset the support against the roof and the hydraulic pressure signal is subsequently sent on to the next roof support.

Instead of opening the re-setting valve 53, the props 6 can also be re-set by operation of valve unit E which, when open, brings the line 25 into communication with the branch supply line 13. Valve unit E can be opened by manually operating lever 34 or, if desired, branch control line 22 could be connected to valve unit E instead of to re-setting valve 53.

When all the roof supports 4 have advanced, the pilot valves 35 are unlocked by manually operating the power source 17 to pressurise the control line 19 and branch control lines 21 to a predetermined value, higher than the predetermined pressure required to open the resetting valve 53, sufiicient to open the locking valves 46 of the roof supports with consequent closure of the pilot valves 35. The pressure in the pilot line 13 then drains away through the bore 45 in the piston rod 41 of each pilot valve 35.

Instead of having a branch control line 22 connected either to the re-setting valve 53 or valve unit E as described above, the valve assembly of each roof support could include a time-operated mechanism triggered by the receipt of the signal in pilot line 18 and arranged so that if, within a predetermined time after receiving the signal, the mechanism had not been rendered inoperative by the presence of a predetermined pressure in line 43, the mechanism would actuate resetting valve 53 or valve unit E to cause resetting of the support.

The resetting of a roof support which has not advanced the full distance may be arranged to cause an indication of this event on the power unit so that the event will not be forgotten and will remain indicated until the indication is manually cancelled.

We claim as our invention:

1. Mining apparatus including a series of advanceable roof supports, each roof support having at least one fluidpressure-operated prop for setting the support against a mine roof, a fluid-pressure-operated jack operable to advance the support, and a valve assembly controlling the supply of fluid under pressure to the prop and to the jack, the valve assembly including a valve which is actuated by the completion of a predetermined advance of the support, with the support released from the roof, to cause resetting of the support against the roof, and the apparatus also including additional means operable to actuate the valve assembly of each support to cause resetting of the support against the roof in the event of failure of the support to advance the predetermined distance.

2. Mining apparatus according to claim 1 wherein each valve assembly is actuated by the satisfactory resetting of its roof support after an advance to send a signal to the valve assembly of the next roof support in the series to cause the said next roof support to undergo an advancing operation.

3. Mining apparatus according to claim 1 wherein the additional means operates to send a resetting signal to all the roof supports in the series.

4. Mining apparatus according to claim 1 wherein the additional means, when operated, supplies a fluid pressure signal to the valve assembly of a roof support to cause resetting of the support.

5. Mining apparatus according to claim 1 wherein the additional means, when operated, actuates the valve which is actuated by the completion of the predetermined advance of the support to cause resetting of the support.

6. Mining apparatus according to claim 1 wherein the additional means, when operated, actuates a valve in the valve assembly other than the valve which is actuated by the completion of the predetermined advance of the support, to cause resetting of the support.

7. Mining apparatus according to claim 1 wherein the additional means is manually operable at a position remote from the roof supports.

References Cited by the Examiner UNITED STATES PATENTS 1,905,065 4/1933 Scholl 91-489 X 2,657,028 10/1953 Joy 6l--45.2 X 2,752,757 7/1956 Joy 91-414 X 2,859,022 11/1958 Frye 6l45.2 X

EDGAR W. GEOGHEGAN, Primary Examiner.

SAMUEL LEVINE, Examiner. 

1. MINING APPARATUS INCLUDING A SERIES OF ADVANCEABLE ROOF SUPPORTS, EACH ROOF SUPPORT HAVING AT LEAST ONE FLUIDPRESSURE-OPERATED PROP FOR SETTING THE SUPPORT AGAINST A MINE ROOF, A FLUID-PRESSURE-OPERATED JACK OPERABLE TO ADVANCE THE SUPPORT, AND A VALVE ASSEMBLY CONTROLLING THE SUPPLY OF FLUID UNDER PRESSURE TO THE PROP AND TO THE JACK, THE VALVE ASSEMBLY INCLUDING A VALVE WHICH IS ACTUATED BY THE COMPLETION OF A PREDETERMINED ADVANCE OF THE SUP- 